What real benefit would you get from seeing a full breakdown of budget allocation? As someone who works in accounting, I see no benefit for publishing that, because on top of providing a spreadsheet ( actually probably a sequence of spreadsheets ) detailing everything, that would be Asset retention and purchase, depreciation, salary and expenses. Trust me, it's boring and usually very complex.
Some are bringing up parallels with being investors, which we aren't. We volunteered money to Obsidian on the sole requirement of return of a video game, plus bonuses based on your donation level. Investors generally own a percentile share in the company or at very least the project for the principle of financial gain at the end result.
We provided donations, not investment, we should not confuse the two.
If you are really interested in all that, their corporate website might release quarterly financial reports to the public, that is if Obsidian is a publicly owned company.